Manufacture of incandescent electric lamps.



No. 766,619; H. HOGGE & J. BAROLLIER.

MANUFACTURE OF INOANDESGENT ELECTRIC LAMPS.

APPLICATION FILED APR. 5, 1904.

N0 MODEL.

PATENTED AUG. 2, 1904.

UNIT D STATES Patented August 2, 1904.

PATENT OFFICE.

HARRY HOGGE, OF ASNIFRES, AND JEAN BAROLLIER, OF PARIS, FRANCE.

MANUFACTURE OF INCANDESOENT ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 766,619, dated August 2, 1904.

Application filed April 5, 190A- To all whom it may concern/.-

Be it known that we, HARRY Hoses, a subject of the King of Great Britain, residing at Asnieres, and J EAN BAR LLIER, a citizen of France, residing at Paris, France, have invented certain new and useful Improvements in the Manufacture of Incandescent Electric Lamps, of which the following is a specification.

This invention relates to improvements in the manufacture of incandescent electric lamps. Heretofore the common metal employed in practice as a conductor through the glass globe of incandescent lamps has been platinum, because it possesses the peculiarity that its coefficient of expansion or dilatation is sensibly the same as that of glass. In the processes which have been hitherto suggested for the employment of less costly metals the problem presented by the difference between the coefficients of expansion of these metals and that of glass has not been satisfactorily solved. In fact, up to the present time the conducting-wires have generally been inserted into the glass globe by fusing the glass round the conductors. It is well understood that under these circumstances, in consequence of the successive heatings and coolings of the lamp, the least difference of expansion between the metal and the glass causes fatal cracks or entrances of air, which render the lamp useless.

The improvements hereinafter described enable any metal whatever-such as copper,

nickel, iron, &c.to be used as conductors in incandescent electric lamps without the difference of expansion between these metals and the glass being in any way inconvenient, the diametral expansion of the conductors being, on the contrary, utilized for obtaining airtightness.

This process consists, essentially, first, in making cylindrical holes in the glass by inserting and fixing therein by fusion and flattening of the glass metallic wires of any suitable kind, which are afterward removed; second, and when the foot is cold in drawingmetallic cylindrical conductors equally in a cold state through the holes in the foot, these metallic conductors having approximately the Serial No. 201,708. (No model.)

same diameter as the holes; third, in afterward applying-a material capable of securing air-tightness when cold-such as a thick solution of india-rubber or copal cement, for example-the air-tightness when hot-that is to say, when thelamp is in use-being secured by the diametral expansion of the conductingwires, which expansion fills the infinitesimally small spaces which previo usly existed between the cold wires and the sides of the holes.

In the accompanying drawings, Figure 1 represents a glass tube intended for the manufacture of a lamp-foot. Fig. 2 represents the foot after the insertion by fusion and pressure of two metallic wires. Fig. 3 represents the foot after the removal of the metallic wires that is to say, showing the two holes ready to receive the conductors. Fig. 4 represents a filament mounted on its metallic conductors ready to be threaded through the holes in the foot. Fig. 5 represents a foot with the conductors which carry the filament threaded through it, and Fig. 6 represents a foot connected with the glass globe and on the hollow part of the foot the material for securing airtightness when cold.

A, Fig. 1, is the glass tube intended to form the foot. In this tube are placed cylindrical metallic wires (0 a, secured therein by fusion and flattening of the glass at A, Fig. 2. These wires are preferably of copper; but they may be of any other suitable metal. After cooling these wires are removed by any suitable means, such as by a dissolving acid or by means of electric energyas by electrolysis, for example. A foot furnished with holes I) 6, Fig. 3, is thus obtained. Into the holes 5 b are threaded the metallic supports 0 c of the filament B, Fig. 4. These supports consist of wires having when cold a diameter approximately equal to that of the holes 6 5. There only remain, therefore, infinitesimally small spaces between the conductors and the sides of the openings. The metallic supports 0 0' may be first threaded through the holes 6 I), the filament being terward.

The supports 0 0 may be of any suitable metal, such as copper, nickel, iron, &c.

mounted on them af- The foot furnished with its filament, Fig. 5, is afterward connected to the glass globe, Fig. 6. The hollow part G of the foot is then filled with a thick solution of india-rubber, copal cement, or any other material capable of making an air-tight joint when cold, and the exhaustion of the lamp is then proceeded with in the ordinary way.

When alamp constructed as above described is put into use,' the conducting-wires expand under the heat produced by the illumination, their diametral expansion filling the infinitesimally small spaces between the cold wires and the sides of the openings, thus rendering the entrance of any matter or air absolutely impossible. hen the wires are cold and contracted, the solution before mentioned,

which is capable of forming an air-tight jointwhen cold, completely prevents the entrance of air. As to the longitudinal expansion, which is considerable as compared with the diametral expansion, this takes place freely without any danger of cracking or leakage, because the cylindrical conductors are free to gxbpand longitudinally in the cylindrical holes Having now particularly described and ascertained the nature of our said invention and serting and fixing therein by fusion and fiattening of the glass, metallic wires of any suitable kind, which are afterward removed; second, in drawing through these holes wires whose diameters are made approximately equal to those of the said holes; and third, in afterward applying a material capable of securing air-tightness when cold, such as a thick solution of india-rubber, the air-tightness when hot, that is to say when the lamp is in use, being secured by the diametral expansion of the conducting-wires, which expansion fills the infinitesimally small spaces which previously existed between the cold wires and the sides of the holes, substantially as described.

In testimony whereof we have hereunto set our hands in presence of two witnesses.

HARRY HOGGE. JEAN BAROLLIER.

Witnesses:

ADoLPH STURM, HANSON O. CoxE. 

